Method for drying burlap bags



May 7, 1935. BROMFIELD 2,000,506

METHOD FOR DRYING BURLAP BAGS Filed Feb. 25, 1932 4m ATTORNEY la d'ifiZZZk/d Patented May 7, 1935 i I j 2,000,505 M f r k METHOD FOR DRYING BUBIAPBAGS r Lloyd '1. Bromfield, New York, N. Y. Application February 25, 1932, Serial No.'5 95,010"- This invention relates to them of drying fiber oughly drying the bags in accordance with the or fabric bags, the invention being more parprinciples of thepresent inventionisillustrated ticularly related toirnprovements in'the-method and described in my companion application, and process of air-drying burlap bags-of the kind Serial No. 612,030, filed May 18,.1932. 5 commonly employed for containing and shipping The principles of the invention and-thepre- 5 sugar. I I 1 .2 i fe'r'red methods and modes of carrying theflsam'e As is well known-burlap bags are produced into e flfect-in a practical waywill be bestlunderfrom strands of hemp, jute or similar plant fibers; stood by referring to the accor'npanying draw- The strands are woven together to form the baging, more or less diagrammatical in character, ging fabric, the character of the weaving being andin'iwhich: i

such as to provide a mesh-like structure with air Figure l isan elevation. and s'ection, showing interstices between the contiguous or touching the j'g'eneralarrangement for subjecting the bag strands. The bagging fabric produced from toithe drying air'; v I these plants possesses the quality of absorbing Fig. 2)represents anexaggerated fragmentary moisture, not only from moisty weather butalso detail section throughthe @material oLthe bag, 15 from the sugar which itselfposs'ess'es high moisshowing the pressuredrying air ac ting on the tureabstracting properties. The materialof the individual, fibers; f I f bags is injured if permitted to'remainin a moist Fig. 3.11s anelevation andfsecticn showingv a state for periods of time. A wet condition is undrying chamber through which a number. of bags desirable since'it adds to the cost of transportamay be bodily moved for I drying at one time, 20 tion of such bags, and also aids in the disintegraand showing also a circulating system for the tion of the fabric of the'bags. Certain methods drying air; and r of drying bags are now in use, butthey have the Fig. 4f representsa top plan. vi w of thee-parts disadvantage of requiring large space and also sho'wri'in Fig; 3." constitutefire hazards for bag stock; and pro- The principles of-my invention and :the mode 25 duce .a very objectionable smoke, believed to be of carrying" them into effect in-a practical way aproduct OIJdiStillfiltiOll 0f the bag'fiber binder. may be employed in connection with anyftype The present invention has for its purpose and of apparatus havinga blower or compressor for object the provision ofan improved method and forcing the dry or heated air or other suitable process for thoroughly drying the bags for filling medium into the bag under pressure,thc appara- 30 or for laying them aside in readiness for filling, tus shown diagrammatically in theaaccompanyand it overcomes the objections above referredto. ing, drawing being presented asan example to According to the invention, the drying medium demonstrate the mode in which the .bag or bags consisting of dry or heated air or other suitable may be subjected to the action of the drying drying gas is introduced into the bag under presmedium foreiifectingv rapid 'andthorough drying. 5 sure while the entire outside of the bag iskept In carryingniy. invention-into effect, the bag free and uncovered in. an atmosphere of lower l0, to be dried, maybehung or suspended from pressure so thatthe. drying. medium iwill anoverheadpIate it having a set of depending rapidly'through thefibers and interstices-.of the fingers I! with which the bag, is: engaged. at its- 40 bag and through all parts of the material of the. open mouth so that the rim edge of its mouth will 40 bag,'frornthe high'pressur inside area to the low be positioned. in contact with the: underface of pressure outside area. 'By introducing the.dry-- the plate. The fingers I2, 01' which there may be ing medium under pressure, the bag is inflated, four in-number, may be, mounted for adjustthereby stretching the fibers and enlarging the ment with respect to one another so as to spread interstices and hence subjecting all parts ofjthe and stretch the bag at itsmouth-for retaining 45 fibers tothe action ofthe flowing medium so as the, bag by frictional engagement. .1 may also to permit rapid absorption of the moisture' perprovide, depending from thefplate "l.l,-a movable vading the'fibers and thereby to effect rapid and auxiliary finger by means of which to further thorough-drying of the same. To ifur'ther hasten stretchthe mouth of the bag and tighten its the drying, the inflated bag'rna'y be bodily mo'ved frictional engagementupon" the fingersso as to 50 through a drying chamber from which the air prevent any accidental dropping movement or is beingconstantly withdrawn in order that the release of the bag v I moisture-laden air, issuing'from the bag, will M denotes a blower or compressor for forcing be promptly removed therefrom. the'drying' medium such as dry orhe'ated air ori An apparatus-suitable for quickly and thor-' other suitable drying gas through theconveying pipe II and theninto the interior of the bag. The dry air, being introduced into the bag under pressure, creates high pressure .within the bag, inflating it and stretching the strands I. thereof and also enlarging the interstices l1 between the strands. 1 v

The pressure of the dry air within the bag exceeds the atmospheric pressure surrounding the bag; and throughout the material of the bag the, drying air will strike and penetrate the strands and pass all around the same, and through the interstices I! in escaping to the low pressure area surrounding the bag. Little streams oi-the drying medium are forced through and around the fibers of the fabric. The moisture. in the fibers and in any sugar, particles adhering to the fibers is absorbed by the dry air and carried of! thereby, thus enabling quick and thorough drying, and this is accomplished without any distilling action upon the natural oils of the fibers. The dry air may be, and preferably'is, heated prior to its introduction into the bag, but it is not heated to an extent sufiicient to'have any distilling action upon the fiber oils, although it is nevertheless heated sufiiciently to eiIect a rapid abstrac-s tion 'of the moisture in the fibers and in the sugar particles adhering thereto, to the end that the adhesion between the fibers and sugar particles will be weakened for hastening and com-v pleting the detachmentand removal'of such particles by the maintained f orce of the airflow itself. Good drying eifects, without causing any distillation of the oils, can be had by using air which is heated about 365 F., impinged against a wet bag, whereas for a drier bag a temperature of about 185 F. is suitable. Since there is no distillation of the oil, there is no odor in the utilization of mymethod.

The-foregoing description relates particularly to washed sugar bags. In case it is desired to dry wet or moist unwashed sugar bags, then the bags are turned inside out, and the air is of a lesser temperature, say about room temperature, and

any sugar particles adhering to the bag can be removed.

a The drying process will be hastened by enclose ing the bag in a'drying chamber is disposed immediately below "the overhead plate H so that the bag will hang freely in the chamber. By the bag through suction, the force of the flow of the drying air is accelerated and the moisture is carried away more rapidly, with the result that thorough drying of the bag is accomplished in a shorter period of time. I

In Figs. 3 and 4, I illustrate. how a number of, bags may, at one time, be subjected to the drying action of heated air blasts, and in connection with this I illustrate acirculating system in which the hot air, after being once used for drying, is

circulated back to the bags for reuse in the drynsn s A In these illustrations, 2| designates an annular drying chamber, the top of which is closed by a rotatable ring plate 22 which supports a number of bagswithin the drying chamber. The ring plate 22 is supported from a hollow rotary d'islr structure 23 by means of air delivery pipes 24. There is one delivery pipe for each bag; and the delivery with a stationary distributing head 2..

aooosoe pipes arelocated in such spaced-apart relation that the bags within the drying chamber 2! will be spaced from one another when inflated. The disk structure 28 is supported by a central distributing head II which is rotatably associated The interior of the disk structure It is divided by radial partitions 21 into compartments or passages 28 of which there is one for each of the delivery pipes 24, while the stationary distributing head is divided into compartments 2. and II by the partition walls and SI, so that air received in the compartment II will pass directly into the passages 28 which come directly therebelow, and further so that air received in the compartment II will pass directly into the passages II which come directly below the same. Air is conducted under pressure into the-compartment 2| through a pipe 3| from the blower or compressor a with which is associated a heating element 33 for heating the air. As the disk structure" revolves, the bags move with it through the orbitafiorded by the annular drying chamber. Through each passage 28 that comes in open communication with the compartment 2|, a blast of the heated air will rush for escape-through the associated delivery pipe N and thence into the interior of the bag suspended fromthe annular plate 22 immediately below such pipe. A suction fan 84 withdraws the air from the drying chamber and forces it through a pipe 3! into the compartment 2!, whence the withdrawn air is used over again in the drying operation, it being obvious that through each e il thatpasses in communication with the compartment II a rush of air will take place into the delivery tube associated with such compartment. A suction fan ll, located in a position diametrically opposite the'suction fan SI, is provided for withdrawing air from the drying chamber ii and for exhausting the withdrawn air through anexhaust pipe I1.

This arrangement providesfor the drying of a number of bags at one timeand the advantage that the bags are bodily in motionthrough the drying chamber while they are subjected to 46 the drying medium under pressure. The bags are moved in their orbit in the direction of the arrow 11 so that they will be first subjected to the drying action of the air flowing from the heating element 33 through the compartment 20. The heated air which reaches the bags through the compartment II, naturally gives upsome of its heat in passing through the bags, so that the air which reaches the bags the compartment 2| is cooler than the air which passes throughth'e compertinent II. Inthis of the air, the bags are first subiectod action by air under pressure at the highest desired temperature, and then to a drying action'by air under pressure at a lower temperature.

In its simplest aspect, my improved method consists in passing dry or heated air imder pres-v sure throughandaroimd'thebagglngstranda so avail myself of all adaptations and modificatitml permitted to me within the spirit and scope of the appended claims.

I claim:-

1. In a continuous method of drying the moist fibrous material of a plurality of bags for containing sugar or the like, the steps which consist in passing separate portions of a quantity of heated air through the fibrous material of individual bags thereby eifecting a preliminary drying of the material of the bags and cooling the air by the absorption of heat therefrom by the material of the bags, subsequently passing separate portions of the air which was cooled during the preliminary drying treatment, through the fibrous material of other individual bags previously subjected to the preliminary drying treatment, continuing the application in a similar. way of separate portions of heated air and in a similar way of separate portions of the cooled air until substantially all of the original moisture content of the fibrous material of all the bags is removed.

2. In a continuous method of drying the moist fibrous material of a plurality of bags for containing sugar or the like, the steps which consist in collecting a quantity of drying air, dividing the quantity into separate portions which are forcibly passed through the fibrous material of the individual bags, thereby effecting a preliminary drying of the same, collecting a quantity of the used air and dividing the same into separate portions which are forcibly passed through other individual bags previously subjected to the preliminary drying treatment, continuing forcible application of portions of the drying air in a similar way and forcible application of used air in a similar way until substantially all of the original moisture content of the fibrous material of all the bags as removed.

3. In a method of removing. enmeshed sugar particles from, and drying, the moist material of a burlap sugar bag, the steps which consist in expanding the mouth-opening edge portion of larging the pores thereof throughout the area of the bag, simultaneously maintaining the fluid of application at a temperature sufliciently high, while avoiding any distilling action of the fiber oils, to cause removal by abstraction of the moisture contained in the fibers and in the therein enmeshed sugar particles, such removal of moisture being effective to bring about a weakening in the adhesion between the sugar particles and the stretched fibers, and simultaneously maintaining the whole amount of fluid. within the bag chamber under a controllable pressural force greater than the weakening adhesion between the sugar particles and the stretched bag fibers, thereby without inherent injury to the bag to detach and remove sugar particles from the fibers thereof while at the same time to remove the moisture content of the fibers and thoroughly dry the bag in its entirety.

LLOYD T. BROMFIELD. 

